BitmapFactory.decodeFile returns null
I want to create a Bitmap from a photo that is on the web.
First i tried to use BitmapFactory.decodeStream
but it returned null because of a bug (http://code.google.com/p/android/issues/detail?id=6066).
now i am saving the image an then using BitmapFactory.decodeFile
but it still returns null.
Any ideas whats wrong or for another workaround?
Thank you!
try {
URL uri = new URL("http://www.witzigundkraus.de/wp-content/uploads/2008/04/scooter-dj-munchen.jpg");
URLConnection connection = uri.openConnection();
Log.i(TAG, "connecting...");
connection.connect();
InputStream is = connection.getInputStream();
//BufferedInputStream bis = new BufferedInputStream(is, 8 * 1024);
File myfile = new File(getApplicationContext().getCacheDir(), "wallpaper.tmp");
myfile.createNewFile();
BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(myfile));
byte buf[]=new byte[1024];
int len;
while((len=is.read(buf))>0)
out.write(buf,0,len);
out.close();
is.close();
Log.d(TAG, String.valueOf(myfile.exists()));
Bitmap bmp = BitmapFactory.decodeFile(myfile.getName());
//Bitmap bmp = BitmapFactory.decodeStream(bis);
Log.i(TAG, "setting bitmap");
Matrix matrix = new Matrix();
int scale = canvas.getWidth()/bmp.getWidth();
matrix.postScale(scale, scale, bmp.getWidth(), bmp.getHeight());
//matrix.postScale(开发者_StackOverflow0.5F, canvas.getWidth()/bmp.getWidth());
Bitmap bmp2 = Bitmap.createScaledBitmap(bmp, canvas.getWidth(), canvas.getHeight(), true);
Paint p = new Paint();
p.setFilterBitmap(true);
try{
canvas.drawBitmap(bmp2, matrix, p);
}catch(NullPointerException exc){
//why do we get this??
Log.d(TAG, "NullPointerException drawing canvas. why?");
return;
}
} catch (MalformedURLException exc){
Log.e(TAG, exc.toString());
return;
} catch (IOException exc){
Log.e(TAG, exc.toString());
return;
}
6-30 17:16:14.558 2253 2253 E AndroidRuntime: java.lang.NullPointerException
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.localfotos.MyWallpaperService$CubeEngine.drawCube(MyWallpaperService.java:212)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.localfotos.MyWallpaperService$CubeEngine.drawFrame(MyWallpaperService.java:159)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.localfotos.MyWallpaperService$CubeEngine.onSurfaceChanged(MyWallpaperService.java:109)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.service.wallpaper.WallpaperService$Engine.updateSurface(WallpaperService.java:543)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.service.wallpaper.WallpaperService$Engine.attach(WallpaperService.java:591)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.service.wallpaper.WallpaperService$IWallpaperEngineWrapper.executeMessage(WallpaperService.java:787)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.android.internal.os.HandlerCaller$MyHandler.handleMessage(HandlerCaller.java:45)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.os.Handler.dispatchMessage(Handler.java:99)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.os.Looper.loop(Looper.java:136)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at android.app.ActivityThread.main(ActivityThread.java:4425)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at java.lang.reflect.Method.invokeNative(Native Method)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at java.lang.reflect.Method.invoke(Method.java:521)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
06-30 17:16:14.558 2253 2253 E AndroidRuntime: at dalvik.system.NativeStart.main(Native Method)
Guy, I also download images from the Internet in my app and its working just fine. The function that I use to download is:
public Bitmap download_Image(String url) {
Bitmap bm = null;
try {
URL aURL = new URL(url);
URLConnection conn = aURL.openConnection();
conn.connect();
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
bm = BitmapFactory.decodeStream(bis);
bis.close();
is.close();
} catch (IOException e) {
Log.e("Hub","Error getting the image from server : " + e.getMessage().toString());
}
return bm;
}
I set another thread to download the image so the UI thread continues to be available. I used AsyncTask (see here) so that the (simplified) doInBackground
function is something like:
@Override
protected Void doInBackground(String... urls) {
return download_Image(urls[0]);
}
I think this page at android's blog explains well something related to this issue.
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